Disteict



(ModeL) W. W. EVANS. DENTAL PLUGGER. No. 279.928.

Patented June 26, 1883.

Waihin N. PETERS. Ph Lmw To all whom it may concern:

.bia, have invented certain new and useful Im- 'atbc.

rounding the shaft 0 and confined between the UNITED STATES PATENTOFFICE.

DENTAL P LUGGE R.

SPECIFICATION forming part of Letters Patent No. 279,928, dated June 26,1883.

Application filed July 1. 1882. (Model) Be it known that I, W.WARRINGTON Evans, of the city of Vashington, District of Columprovementsin Dental Pluggers, of which the following is a specification, referencebeing had to the accompanying drawings, and to the letters of referencemarked thereon.

My invention relates to improvements in that class of instruments inwhich the blow for condensing the gold or filling material is given by amallet placed within the case and operated by the attachment of theinstrument-to a dental engine or other motive power.

The object of the invention is to improve the character of the blowgiven and to condense the gold or other filling substance moreeffectually than .is ordinarily done, and with less inconvenience to thepatient.

A further object is to enable the operator to conveniently control theforce of the blows, as also to discontinue them temporarily without thenecessity of stopping the engine.

A further object is to obtain simplicity, strength, and cheapness inconstruction.

In the drawings, Figure 1 represents a longitudinal section of theinstrument. Figs. 2, 3, 4, 5, 6, 7, and 8 are details of the invention,hereinafter particularly described. 7

Similar letters of reference indicate similar parts in the respectivefigures.

A is the outer tubular casing of the instrument, made of any suitablematerial. Each end of the casing A is internally threaded, as

At the operative or tool end of the instrument is formed on or attachedto the easing aring or proj ection, b, which gives strength thereto andreceives a pin or set-screw, b, which projects within the casing A, fora purpose hereinafter described.

B is the tubular bearing or support for the tool-holderor reaction-shaft0, Fig. 3, which bearing is screwed into the end b of the casing A. Thebearing B is provided with a cylindrical bore, which receives a spring,0, surcollar 0 of the shaft 0 and the end 0 of the tip D, which tip isscrewed into the threaded outer extremity of the bearing B. The tip D,Fig. 4, is slotted at one side at d, which slot receives a pin or screw,(1, projecting from a side of the tool support or shaft 0. The inner endof the shaft 0 is provided with a cylindrical hard-rubber or lead nut,e.

Vithin the casing A is placed the cylindrical. mallet E, Fig. 5, havingbearings ff at its ends only, which parts are neatly fitted to the innersurface or bore of the casing, the greater part of the length of themalletnot having contact'with the casing, whereby there is but littlefriction caused by thelongitudinal movement of the mallet within thecasing.

The outer end of the'mallet is provided with a cam-face, g, which faceis also cylindrically bored or socketed, as shown by g, a lead or rubberwasher, 9, being inserted within and at the bottom of the cavity thusproduced. The end of the shaft or tool holder 0, with its rubber or leadnut e, is adapted to enter the cavity g, the nut impinging upon the leadwasher in the operation of the instrument, as hereinafter described. Theother end of the mallet is also provided with a cylindrical socket orcavity, 9', and with a longitudinal bore, l2, concentric therewith andof smaller. diameter, extending from h to h.

The shaft which connects the instrument, with the dental engine isrepresented by F,.the

outer end of the shaft entering the longitudinal bore h of the mallet E.That part of the shaft F which enters the mallet is slotted orkey-seated at i, which seat or slot is entered .by one or more keys, k,which project within the bore .71 These keys are attached to the mallet.bybeing screwed into it from the outside or perimeter thereof, theirheads being turned or filed flush with it, andthe inner projections,constituting the keys, being shaped to accurately fit the keyway i ofthe shaft F. I prefer to use two or more keys, k, in order to secure abetter or longer connection between themallet E and the shaft F, inorder to resist the torsional strain to which the parts are subjected inoperation.

It will be understood that by the connection formed between the mallet Eandshaft F by the keyway and keys i and 7c, respectively, a rotarymotion given to the shaft F is also imparted to the mallet, but that themallet is capable of longitudinal movement independently of the shaft.Surrounding the shaft F is placed a helical spring or springs, Z, theouter end of the spring resting within the cylindrical cavity of themallet, and the opposite end abu ting against the face of a slidingthimble, m. ing rotation is imparted to the shaft F, and

(Shown in perspective-in Fig. 6.) The thimble m is provided with pins m,projecting from its periphery, which pins rest in slots m cut in thesides of the casing. By this construction the thimble m is made capableof movement longitudinally of the casing, thereby acting, when movedtoward the mallet, to compress the spring or springs Z. The extendedsides or hollow cylindrical portion of the thimble m serves to cover theslots m in the casing and exclude dust, dirt, &c., from the interiorthereof, and to prevent the passage of the oil or lubricant therefrom.The longitudinal. movement of the thimble m is effected in a mannerdescribed hereinafter. A cap, 11, Fig. 7, screws within the end of thecasing A. The central portion of the cap a is bored longitudinally toreceive and serve as a bearing for the outer end of the coupling-shaftF. The part of the shaft which is supported by the cap or is shown inFig. 8, there being onthe shaft collars o 0, having aspace, 0", betweenthem. Apin, a, is inserted from the outer part of the cap a, the innerend of the pin extending into the space 0. The cap a is provided with amilled outer surface, a, by means of which it is screwed into the endcof the casing A. G is an internallythreaded tension-adj uster, whichscrews upon a thread formed upon the outside of the casing A, whichtension-adjuster is in contact with the pins on of the thimble on, so

that the forward travel of the tension-adjuster G effects thecompression of the spring or springs Z, while its backward movementallows their expansion, the pins mmovingin the slots m of the casing A.

The cylindrical internallyscrewthreaded part of the cap it receives thescrew end q of the flexible shaft-support H, having a milled outersurface q. \Vithin the support H is placed longitudinally thereof theshaft-coup ling I, which has the conical flange .9, which rests or has abearing in a correspondinglyshaped cavity formed in the end of thesupport H. The end of the shaft F is of the ordinary construction,enabling it to connect with the shaft-coupling I, whose connecting endis provided with a socket appropriate for the purpose, whereby therotary movement of the shaft-coupling may be communicated to the shaftF. The union between the end of the shaft F and the socket of theshattcoupling I may be effected by means of a cross-pin, t. The oppositeend, :0, of the shaft-coupling I is cylindrically bored to receive andhold the end of the flexible shaft of the dental engine, and theadjacent end, t, of the support H is cylindrical and internally threadedto receive and secure the non-rotatory part of the flexible shaft. Iprefer to make the part i sepa rate from the rest ofthe support H andsccured thereto by pins or screws 15',- but itmay be made homogeneoustherewith.

The operation of the instrument is as follows: Rotary motion having beengiven to the flexible shaft of the dental engine, correspondthe blow tothe plugger. eedes again by contact being renewed between by reason ofthe keyeonnection between said shaft and the mallet E the same movementis given thereto. The adjustment of the spring Z is such that the camend of the mallet impinges with some degree of force on the fixed pin 1/passing through the ring I) and projecting into the casing. In eachrevolution. of the mallet the contact between its cam-face and the pin 6causes the mallet to be forced back a distance equivalent to the pitchof the cam. hen the termination of the cam-face is brought opposite thepin, the force of the spring or springs Z effects the sudden projectionforward of the mallet, its washer y striking against the hard-rubber nutc of the shaft.

0, compressing its spring 0 and imparting As the mallet rethe spiral ofthe cam-face and the pin 1/ the shaft 0 is left free to be retracted,and its return is effected by the action of the spring 0, which carriesback the shaft to a position somewhat beyond the pin 12, to a positionadapting the nut e to receive in a proper manner the .next blow of themallet. The relative positions occupied before the blow is struck by thenut 0, pin 7/, and cam-face are such as to regulate and definitelydetermine the length of the stroke given to the plugger, which it willbe seen must invariably be the same unless the adjustment of the partsis changed. Fig. 1 shows the plugger at its downward stroke, while Fig.2 represents the mallet at its backstroke or limit of move" ment, andthe plugger retracted by the action of the spring 0.

The effect of the contact between the hard rubber nut e and the leadwasher g is to soft- TOO en the character of the blow by deadeningthesound or making the blow practically noiseless to the ear of thepatient.

Near the outer end of the tool-holder or reaction-sl1aft O is theordinary locking-ring, c. Should the operator desire to temporarilydiscontinue the strokes, he can do this by pressing his finger againstthe ring c, or, should he prefer it, the pin (7/, whereupon the nut endof the shaft 0 will be made to push the cam-face of the mallet back outof contact with the pin 1/, so that the mallet in its revolutions willbe inoperative to give movement to the plugger.

The pin (1 slides within the slot (1 of the tubular support B and thecorresponding slot, (7, in the screw end of the tip 1).

The shaft-support H is applicable to a drilling-instrument on theplugging-instrument being detached, thus dispensing with an unnecessaryamount of mechanism.

I am aware that heretofore the force of the spring effecting the blowhas been varied in accordance with end-pressure on the tool, anddisclaim, generally, the invention of means for accomplishing suchresult. I also disclaim, generally considered, a sliding cam an elementin a dental plugger.

Having described my invention, I claim- IIO 1. Ina dental plugger, thecombination of a tubular casing, a fixed pin extending thereinto, amallet adapted to rotate and slide within the casing and having acam-face to operate on or against said pin, and a spring for maintainingcontact between the cam-face and pin, substantially as set forth.

2. In a dental plugger, a tubular casing, fixed pin, and aspring-operated mallet having a cam'face and adapted to revolve andslide in said casing, combined with a tubular support, a shaft ortool-holder capable of sliding movement therein, and a spring forretracting the sliding shaft, substantially as set forth.

3. The combination of a tubular casing, a

fixed pin, a revolving and sliding mallet with mallet, tensionspring,sliding thimble having pins extending through the slots of the casing,and a tension-adjuster screwed upon the outsideof the casing andengaging with the pins of the thimble, substantially as set forth.

6. The combination of the casing, screw-cap n, pin a, coupling-shaft,with collars o o, and space '0", substantially as set forth.

7. The combination of support H and shaftcoupling I with conical flangehaving a bearing in the support H, substantially as set forth.

8. The combination of cap a, support H, and shaft-coupling I,substantially as set'forth.

9. A shaft-support having an outer male thread and aninternally-threaded cylindrical extension, and provided, further,' witha suitable interior bearing adapted to receive a revolubleshaft-coupling, said support constituting a device detachable from theinstrument, substantially as and for the purposes set forth.

10. The combination, in a dental plugger, of a casing with a cylindricalmallet, the latter having annular bearings which only are in contactwith the interior of the casing, thereby lessening friction in theoperation of the mallet, substantially as set forth.

In testimony whereof I have hereunto set my hand this 24th day of June,1882.

, I. \VARRINGTON EVANS.

\Vitnesses:

Gnonen H. HOWARD, W. T. COLE.

